Developing method and developing apparatus

ABSTRACT

A developing method including a developing step in which, while a wafer horizontally held by a spin chuck is being rotated, the wafer is developed by supplying a developer onto a surface of the wafer, wherein provided before the developing step is a pre-wetting step in which, simultaneously with the developer being supplied from a first nozzle that is located on a position near a central part of the surface of the rotating wafer, a deionized water as a second liquid is supplied from a second nozzle that is located on a position nearer to an outer peripheral part of the wafer than the first nozzle, to thereby spread out the developer in the rotating direction of the wafer by a wall that is formed by the deionized water flowing to the outer peripheral side of the wafer with the rotation of the wafer.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromthe prior Japanese Patent Application No. 2008-157560 filed on Jun. 17,2008, the entire contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a developing method and a developingapparatus configured to develop a substrate whose surface has beencoated with a resist and exposed.

BACKGROUND OF THE INVENTION

In general, when a semiconductor device is manufactured, a photoresistis coated on a substrate such as a semiconductor wafer, the thus formedresist film is exposed in accordance with a predetermined circuitpattern, and the exposed pattern is developed so as to form a circuitpattern in the resist film.

In this photolithographic step, there is generally used a system inwhich an exposure apparatus is connected to a coating and developingapparatus for coating and developing a resist.

As a conventional developing apparatus, there has been known, forexample, a rotational developing paddle type in which a developer issupplied to a substrate which is being rotated, the developer is spreadout over all the substrate, a developer is then supplied from a partnear a center of the substrate while the rotational speed of thesubstrate is decreased, and a developer film (paddle) is formed by theaccumulated developer.

In such a developing apparatus, there has been known a method in which adeionized water is supplied to a surface of a substrate before thedeveloping process, in order to improve a wetting property (see, forexample, JP2005-210059A).

Meanwhile, in order to cope with further miniaturization of a devicepattern and further thinning of a film, there is an ongoing demand forraising a resolution of exposure. As one of the methods for raising theresolution of exposure, there is known an immersion exposure method inwhich a substrate is exposed with a light-transmittable liquid layerbeing formed on a surface of the substrate, in order to raise theresolution by improving an exposure technique by an existing lightsource such as argon fluoride (ArF) light source. In this immersionexposure technique, under the condition that a liquid film of adeionized water is formed between a lens and a surface of a substrate, alight ray emitted from the light source passes through the lens andtransmits the liquid film so as to be irradiated on the substrate,whereby a predetermined resist pattern (circuit pattern) is transferredto the resist.

In the liquid exposure technique, a highly water-repellent resist(non-topcoat resist) is sometimes used, or a highly water-repellentprotective film (upper protective film) is sometimes used on a resist.In order that a deionized water is stabilized lest droplets of thedeionized water remain on a substrate so as to improve a productivity,there is used the non-topcoat resist that does not require the upperprotective film.

SUMMARY OF THE INVENTION

For example, since the non-topcoat resist is highly hydrophobic, evenwhen a deionized water is supplied to a substrate surface before thedeveloping process by using the technique described in JP2005-210059A, asurface of the resist film cannot obtain a sufficient wetting property.As a result, the developer on the substrate is repelled and spun off.Thus, there is a problem in that it is difficult to form a developerfilm (paddle) on the substrate surface even when a supply amount of thedeveloper is increased.

The present invention has been made in view of the above circumstances.The object of the present invention is to provide a developing methodand a developing apparatus capable efficiently forming a developer filmand thus stabilizing a developing process, by improving a wettingproperty of a surface of a resist film formed on a substrate that ismade hydrophobic.

In order to solve the above problem, the developing method of thepresent invention is a developing method comprising a developing step inwhich, while a horizontally held substrate is being rotated, thesubstrate is developed by supplying a developer onto a surface of thesubstrate, wherein provided before the developing step is a pre-wettingstep in which, simultaneously with the developer being supplied from afirst nozzle that is located on a position near a central part of thesurface of the rotating substrate, a second liquid is supplied from asecond nozzle that is located on a position nearer to an outerperipheral part of the substrate than the first nozzle, to therebyspread out the developer in the rotating direction of the substrate by awall that is formed by the second liquid flowing to the outer peripheralside of the substrate with the rotation of the substrate.

In addition, the present invention is a developing method comprising adeveloping step in which, while a horizontally held substrate is beingrotated, the substrate is developed by supplying a developer onto asurface of the substrate, wherein provided before the developing step isa pre-wetting step in which, simultaneously with the developer beingsupplied from a first nozzle that is located on a position near acentral part of the surface of the rotating substrate, a second liquidis supplied from a second nozzle that is located on a position nearer toan outer peripheral part of the substrate than the first nozzle, and thefirst nozzle and the second nozzle are moved in a direction connectingthe central part and the outer peripheral part of the substrate, tothereby spread out the developer in the rotating direction of thesubstrate by a wall that is formed by the second liquid flowing to theouter peripheral side of the substrate with the rotation of thesubstrate.

In this invention, the second liquid is a deionized water. A surfacetension value of the developer is larger than that of the second liquid.A specific gravity of the developer is larger than that of the secondliquid. A viscosity of the developer is larger than that of the secondliquid.

In the developing method of this invention, it is preferable that arotational speed of the substrate is between 250 rpm and 3000 rpm.

This is because, when the rotational speed of the substrate is smallerthan 250 rpm, the liquids (developer and deionized water) may not besufficiently spread out, and when the rotational speed of the substrateis larger than 3000 rpm, the liquid may be scattered on the outerperipheral side whereby a pre-wetting film cannot be formed.

In the developing method of this invention, it is preferable that beforethe developer and the second liquid are simultaneously supplied, thereis provided a step in which the second nozzle is moved to a positionabove the central part of the substrate, and the second liquid issupplied onto the substrate surface.

In addition, a developing apparatus of this invention is a developingapparatus configured to rotate a horizontally held substrate, and todevelop the substrate by supplying a developer onto a surface of thesubstrate, the developing apparatus comprising: a substrate holdingmeans configured to horizontally hold the substrate; a rotatingmechanism configured to rotate the substrate in a horizontal plane; afirst nozzle configured to supply the developer onto the substratesurface, while the substrate is being rotated by the rotating mechanism;a second nozzle configured to supply a second liquid onto the substratesurface, the second nozzle being located on a position nearer to anouter peripheral part of the substrate than the first nozzle; and acontrol means configured to control the rotating mechanism, the firstnozzle, and the second nozzle; wherein, before a developing step inwhich the developer is supplied to the substrate, the control meansdrives the rotating mechanism so as to rotate the substrate, andperforms a pre-wetting process in which, simultaneously with thedeveloper being supplied from the first nozzle that is located on aposition near a central part of the surface of the substrate, the secondliquid is supplied from the second nozzle that is located on a positionnearer to the outer peripheral part of the substrate than the firstnozzle, to thereby spread out the developer in the rotating direction ofthe substrate by a wall that is formed by the second liquid flowing tothe outer peripheral side of the substrate with the rotation of thesubstrate.

In addition, the present invention is a developing apparatus configuredto rotate a horizontally held substrate, and to develop the substrate bysupplying a developer onto a surface of the substrate, the developingapparatus comprising: a substrate holding means configured tohorizontally hold the substrate; a rotating mechanism configured torotate the substrate in a horizontal plane; a first nozzle configured tosupply a developer onto the substrate surface, while the substrate isbeing rotated by the rotating mechanism; a second nozzle configured tosupply a second liquid onto the substrate surface, the second nozzlebeing located on a position nearer to an outer peripheral part of thesubstrate than the first nozzle; a nozzle moving mechanism configured tomove the first nozzle and the second nozzle in a direction connectingthe central part and the outer peripheral part of the substrate; and acontrol means configured to control the rotating mechanism, the nozzlemoving mechanism, the first nozzle, and the second nozzle; wherein,before a developing step in which the developer is supplied to thesubstrate, the control means drives the rotating mechanism so as torotate the substrate, and performs a pre-wetting process in which,simultaneously with the developer being supplied from the first nozzlethat is located on a position near a central part of the surface of thesubstrate, the second liquid is supplied from the second nozzle that islocated on a position nearer to the outer peripheral part of thesubstrate than the first nozzle, and drives the nozzle moving mechanismso as to move the first nozzle and the second nozzle in a directionconnecting the central part and the outer peripheral part of thesubstrate, to thereby spread out the developer in the rotating directionof the substrate by a wall that is formed by the second liquid flowingto the outer peripheral side of the substrate with the rotation of thesubstrate.

In the developing apparatus of this invention, the second liquid is adeionized water. In addition, it is preferable that a rotational speedof the substrate rotated by the rotating mechanism is between 250 rpmand 3000 rpm.

In addition, it is preferable that before the first nozzle and thesecond nozzle are moved and the developer and the second liquid aresimultaneously supplied, the control means moves the second nozzle to aposition above the central part of the substrate so as to supply thesecond liquid onto the substrate surface.

According to the present invention, before the developing process,simultaneously with the developer being supplied from the first nozzlethat is located on a position near the central part of the surface ofthe rotating substrate, the second liquid is supplied from the secondnozzle that is located on a position nearer to the outer peripheral partof the substrate than the first nozzle, to thereby spread out thedeveloper in the rotating direction of the substrate by a wall that isformed by the second liquid flowing to the outer peripheral side of thesubstrate with the rotation of the substrate. Thus, the developer can beuniformly spread out on the substrate surface, and a wetting property ofthe substrate surface can be enhanced.

According to the present invention, before the developing process, thefirst nozzle and the second nozzle are moved in a direction connectingthe central part and the outer peripheral part of the substrate, tothereby spread out the developer in the rotating direction of thesubstrate by a wall that is formed by the second liquid flowing theouter peripheral side of the substrate with the rotation of thesubstrate. Thus, the developer can be uniformly spread out on thesubstrate surface, and a wetting property of the substrate surface canbe enhanced.

In addition, according to the present invention, before the developerand the second liquid are simultaneously supplied, the second nozzle ismoved to a position above the central part of the substrate so as tosupply the second liquid onto the substrate surface. Thus, an adheringproperty of the developer to the substrate can be improved at an initialstage of the pre-wetting step.

According to the present invention, due to the above structure, thewetting property of a surface of a resist film formed on the substratethat is made hydrophobic can be improved, whereby a developer film canbe efficiently formed and thus the developing process can be stabilized.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic plan view showing a process system as a whole inwhich an exposure apparatus is connected to a coating and developingapparatus to which a developing apparatus according to the presentinvention is applied.

FIG. 2 is a schematic perspective view of the processing system.

FIG. 3 is a schematic sectional view showing the developing apparatusaccording to the present invention.

FIG. 4 is a schematic plan view showing the developing apparatus.

FIG. 5 is a schematic plan view showing a principle of a pre-wettingprocess in this invention.

FIG. 6 is a view for explaining a first embodiment of the pre-wettingstep in this invention.

FIG. 7 is a view for explaining a second embodiment of the pre-wettingstep in this invention.

DETAILED DESCRIPTION OF THE INVENTION

One embodiment of this invention is described herebelow with referenceto the accompanying drawings.

FIG. 1 is a schematic plan view showing a process system as a whole inwhich an exposure apparatus is connected to a coating and developingapparatus to which a developing apparatus according to the presentinvention is applied. FIG. 2 is a schematic perspective view of theprocessing system.

The processing system includes: a carrier station 1 for loading andunloading a carrier 10 capable of hermetically containing a pluralityof, e.g., twenty-five semiconductor wafers W (hereinafter simplyreferred to as “wafer”) as substrates to be processed; a processing part2 for coating a resist on a wafer W and develop the wafer W that istaken out from the carrier station 1; an exposure part 4 forimmersion-exposing a surface of the wafer W, with a light-transmittableliquid layer being formed on the surface of the wafer W; and aninterface part 3 connected between the processing part 2 and theexposure part 4 so that the wafer W is transferred therebetween.

The carrier station 1 includes: a stage 11 on which a plurality ofcarriers 10 can be placed in a line; an opening and closing part 12formed in a front wall surface when viewed from the stage 11; and aconveying means A1 for taking out a wafer W from the carrier 10 throughthe opening and closing part 12.

The interface part 3 is composed of a first transfer chamber 3A and asecond transfer chamber 3B that are interposed between the processingpart 2 and the exposure part 4 in a back and forth direction. The firsttransfer chamber 3A and the second transfer chamber 3B are respectivelyprovided with a first wafer transfer part 30A and a second wafertransfer part 30B.

The processing part 2 whose circumference is surrounded by a housing 20is connected to a rear side of the carrier station 1. The processingpart 2 is provided with, in an alternating arrangement manner, shelfunits U1, U2 and U3 in which heating units and cooling units arearranged in a tier-like manner, liquid processing units U4 and U5, andmain transfer means A2 and A3 for transferring a wafer W between therespective units, in this order from the front. The main transfer meansA2 and A3 are located in a space surrounded by a partition wall 21including one surface part on a side of the shelf units U1, U2, and U3that are arranged in the back and forth direction when viewed from thecarrier station 1, one surface part on a side of, e.g., the right-sideliquid processing units U4 and U5 which are described below, and a rearsurface part as a left-side surface. Disposed between the carrierstation 1 and the processing part 2 and between the processing part 2and the interface part 3 are temperature-and-humidity adjusting units 22each having a temperature adjusting apparatus and a duct for adjusting atemperature and a humidity of a process liquid used in the respectiveunits.

The shelf units U1, U2 and U3 are structured by stacking, at a pluralityof, e.g., ten levels, various units for performing a preprocess and apostprocess for a process performed by the liquid processing units U4and U5. Combinations of the various units include a heating unit (HP)for heating (baking) a wafer W and a cooling unit (CPL) for cooling awafer W. As shown in FIG. 2, the liquid processing units U4 and U5 arestructured by stacking, at a plurality of, e.g., five levels, a bottomanti-reflection film coating unit (BCT) 23 for coating ananti-reflection film on a chemical-liquid containing part such as aresist and a developer, a coating unit (COT) 24, and a developing unit(DEV) for supplying a developer to a wafer W so as to develop the same,for example. A developing apparatus 50 according to this invention isdisposed in the developing unit (DEV) 25.

As shown in FIGS. 3 and 4, the developing apparatus 50 includes a spinchuck 40 disposed in a casing 51 having a loading and unloading port 51a for a wafer W. The spin chuck 40 serves as a substrate holding meansfor horizontally holds a wafer W by absorbing a central part of a rearsurface of the wafer W. The loading and unloading port 51 a is equippedwith a shutter 51 b that can be opened and closed.

The spin chuck 40 is coupled to, e.g., a rotating mechanism 42 such as aservomotor through a shaft part 41. Due to the rotating mechanism 42,the spin chuck 40 can be rotated while holding a wafer W. The rotatingmechanism 42 is electrically connected to a controller 60 as a controlmeans, so that a rotational speed of the spin chuck 40 can be controlledbased on a control signal from the controller 60.

A cup 43 is disposed so as to surround a lateral side of a wafer W heldby the spin chuck 40. The cup 43 is composed of a cylindrical outer cup43 a and a tubular inner cup 43 b whose upper part is inclined inward.The outer cup 43 a can be moved in an up and down direction by anelevating mechanism 44 such as a cylinder connected to a lower end ofthe outer cup 43 a, and the inner cup 43 b can be moved in the up anddown direction by being pushed up by a stepped part formed on an innercircumferential surface on a lower end side of the outer cup 43 a. Theelevating mechanism 44 is electrically connected to the controller 60,so that the outer cup 43 a can be moved in the up and down directionbased on a control signal from the controller 60.

A circular plate 45 is disposed below the spin chuck 40. A liquidreceiving part 46 having a recessed cross-section is disposed outsidethe circular plate 45 to surround the same. A drain outlet port 47 isformed in a bottom surface of the liquid receiving part 46, so that adeveloper and a rinse liquid, which drop or spin off from the wafer Wand stored in the liquid receiving part 46, can be discharged outsidethe apparatus through the drain outlet port 47. A ring member 48 havinga chevron-like cross-section is disposed outside the circular plate 45.Although not shown, a plurality of, e.g., three elevating pins assubstrate supporting pins are disposed to pass through the circularplate 45. Owing to a cooperation of the elevating pins and a not-shownsubstrate transfer means, a wafer W can be transferred to the spin chuck40.

On the other hand, disposed above the wafer W held by the spin chuck 40are: a first developer supply nozzle 52 (hereinafter referred to as“developer nozzle 52”) capable of being moved in the up and downdirection and moved in the horizontal direction, the developer nozzle 52being opposed to a central part of a front surface of the wafer W with agap between the developer nozzle 52 and the wafer W; and a secondpre-wetting deionized-water nozzle 53 (hereinafter referred to as“deionized-water nozzle 53”) that is located on a position nearer to anouter peripheral part of the wafer W than the developer nozzle 52, thedeionized-water nozzle 53 being configured to supply a second liquidsuch as a deionized water to the front surface of the wafer W.

The developer nozzle 52 is equipped with a slit-like spout (not shown)for discharging (supplying) a developer in a strip-like manner. Thespout is located such that a length direction thereof is oriented fromthe central part toward the outer peripheral part of the wafer W, forexample. Not limited to the spout that is extended along a straight line(radius) oriented from the central part toward the outer peripheral partof the wafer W, the spout may intersect the straight line at a slightangle.

The developer nozzle 52 and the deionized-water nozzle 53 are supportedon one end of a nozzle arm 54A. The other end of the nozzle arm 54A iscoupled to a movable table 55A having a not-shown elevating mechanism.The movable table 55A is configured to be laterally movable along aguide member 57A extending in an X direction, by means of a nozzlemoving mechanism 56A such as a ball screw and a timing belt. Due to thisstructure, when the nozzle moving mechanism 56A is driven, the developernozzle 52 and the deionized-water nozzle 53 are moved along the straightline (radius) oriented from the central part toward the outer peripheralpart of the wafer W.

Disposed on one outside part of the cup 43 is a standby part 59A for thedeveloper nozzle 52 and the deionized-water nozzle 53. The standby part59A cleans a nozzle end of the developer nozzle 52, for example.

In addition, disposed above the wafer W held by the spin chuck 40 is arinse nozzle 58 for discharging (supplying) a rinse liquid such asdeionized water, the rinse nozzle 58 being opposed to the central partof the front surface of the wafer W with a gap between the rinse nozzle58 and the wafer W. The rinse nozzle 58 is capable of being moved in theup and down direction and moved in the horizontal direction.

The rinse nozzle 58 is supported on one end of a nozzle arm 54B. Theother end of the nozzle arm 54B is coupled to a movable table 55B havinga not-shown elevating mechanism. The movable table 55B is configured tobe laterally movable along a guide member 57B extending in the Xdirection, by means of a nozzle moving mechanism 56B such as a ballscrew and a timing belt. Disposed on the other outside part of the cup43 is a standby part 59B for the rinse nozzle 58.

The developer nozzle 52 is connected to a developer supply source 71through a developer supply duct 70 in which an opening and closing valveV1 is disposed. The deionized-water nozzle 53 is connected to a branchduct 74. The branch duct 74 is connected via a switching valve V3 to adeionized-water supply duct 72 connecting the rinse nozzle 58 and adeionized-water supply source 73. An opening and closing valve V2 isdisposed in the deionized-water supply duct 72.

The nozzle moving mechanisms 56A and 56B, the opening and closing valvesV1 and V2, and the switching valve V3 are respectively electricallyconnected to the controller 60, so that the developer nozzle 52 and thedeionized-water nozzle 53 can be horizontally moved, the rinse nozzle 58can be horizontally moved. the opening and closing valves V1 and V2 canbe driven to be opened and closed, and the switching valve V3 can bedriven to be switched, based on a control signal previously stored inthe controller 60.

By means of the control of the controller 60, a pre-wetting process canbe performed before a developing process in which a developer issupplied to a wafer W. Namely, as shown in FIG. 5, there is performedthe pre-wetting process in which, simultaneously with a developer 100being discharged (supplied) from the developer nozzle 52 that is locatedon a position near a central part of a front surface of a wafer W thatis being rotated by driving the rotating mechanism 42, a deionized water200 is discharged (supplied) from the deionized-water nozzle 53 that islocated on a position nearer to an outer peripheral part of the wafer Wthan the developer nozzle 52, to thereby spread out the developer 100 inthe rotating direction of the wafer W by a wall 300 that is formed bythe deionized water 200 flowing to the outer peripheral side of thewafer W with the rotation of the wafer W.

Next, the pre-wetting process is concretely described with reference toFIGS. 6 and 7. FIG. 6 is a view for explaining a first embodiment of thepre-wetting step. In the first embodiment, the rotating mechanism 42 isfirstly driven to rotate a wafer W. At this time, a rotational speed ofthe wafer W is within a range between 250 rpm and 3000 rpm, e.g., at1500 rpm. While the wafer W is being rotated, the nozzle movingmechanism 56A is driven so as to move the deionized-water nozzle 53 to aposition above a central part of the wafer W (see, FIG. 6( a)). Then, adeionized water 200 is discharged (supplied) from the deionized-waternozzle 53 onto the central part of the wafer surface. (see, FIG. 6( b)).Thus, an adhering property of a developer to the wafer W can be improvedat an initial stage of the pre-wetting step. Following thereto, thenozzle moving mechanism 56A is driven so as to move the developer nozzle52 to the position above the central part of the wafer W, and adeveloper 100 is discharged (supplied) from the developer nozzle 52 ontothe central part of the wafer surface (see, FIG. 6( c)). Under thiscondition, as described above, since the deionized water 200 is alsodischarged (supplied) from the deionized-water nozzle 53 that is locatedon a position nearer to the outer peripheral part of the wafer W thanthe developer nozzle 52, there can be performed the pre-wetting processin which the developer 100 is spread out in the rotating direction ofthe wafer W by a wall 300 that is formed by the deionized water 200flowing to the outer peripheral side of the wafer W with the rotation ofthe wafer W (see, FIG. 5).

FIG. 7 is a view for explaining a second embodiment of the pre-wettingstep. In the second embodiment, similarly to the first embodiment, therotating mechanism 42 is firstly rotated to rotate a wafer W. Then,while the wafer W is being rotated, the nozzle moving mechanism 56A isdriven so as to move the deionized-water nozzle 53 to a position above acentral part of the wafer W (see, FIG. 7( a)). Then, a deionized water200 is discharged (supplied) from the deionized-water nozzle 53 onto thecentral part of the wafer surface (see, FIG. 7( b)). Following thereto,the nozzle moving mechanism 56A is driven so as to move the developernozzle 52 to the position above the central part of the wafer W, and adeveloper 100 is discharged (supplied) from the developer nozzle 52 ontothe central part of the wafer surface (see, FIG. 7( c)). Under thiscondition, the deionized water 200 is also discharged (supplied) fromthe deionized-water nozzle 53 that is located on a position nearer tothe outer peripheral part of the wafer W than the developer nozzle 52.Under this condition, the nozzle moving mechanism 56A is moved so as tomove the developer nozzle 52 and the deionized-water nozzle 53 along astraight line (radius) oriented from the central part toward the outerperipheral part of the wafer W (see, FIG. 7( b)). Thus, as describedabove, there can be performed the pre-wetting process in which thedeveloper 100 is spread out in the rotating direction of the wafer W bya wall 300 that is formed by the deionized water 200 flowing to theouter peripheral side of the wafer W with the rotation of the wafer W(see, FIG. 5). After the developer nozzle 52 and the deionized-water 53have been moved to the outer peripheral side of the wafer W, thedeveloper nozzle 52 and the deionized-water nozzle 53 may be moved alongthe straight line (radius) oriented from the outer peripheral parttoward the central part of the wafer W, while the developer 100 and thedeionized water 200 are being discharged (supplied) (see, FIG. 7( e)).

In the above embodiments, a surface tension value of the developer 100is larger than that of the deionized water 200 used as the secondliquid. In addition, since the developer 100 has a larger specificgravity and a larger viscosity than those of the deionized water 200,the wetting property of the wafer surface can be enhanced.

It is possible to use a liquid other than a deionized water as thesecond liquid. However, it is preferable that such a liquid has theaforementioned properties, i.e., a smaller surface tension value, asmaller specific gravity, and a smaller viscosity than those of adeveloper.

After the pre-wetting process has been performed, a series of processessuch as a developing liquid, a rinse process, and a drying process areperformed in this order. Namely, the developing process is performedsuch that the nozzle moving mechanism 56A is moved so as to move thedeveloper nozzle 52 to the position above the central part of the wafersurface, and the developer nozzle 52 is moved along the straight line(radius) oriented from the central part toward the outer peripheral partof the wafer W, while the developer 100 is being discharged (supplied)onto the surface of the rotating wafer W. After the developing process,the rinse process for rinsing the wafer surface is performed such thatthe nozzle moving mechanism 56B is moved so as to move the rinse nozzle58 to the position above the central part of the wafer surface, and arinse liquid, i.e., a deionized water is discharged (supplied) from therinse nozzle 58 onto the surface of the rotating wafer W so as to rinseaway the developer containing a resist soluble component remaining onthe wafer surface. After the rinse process, the spin-drying process isperformed such that the rotating mechanism 42 is driven to rotate thewafer W at a high rotational speed such as 200 rpm, whereby the liquidremaining on the wafer surface is spun off.

Next, there is briefly described a procedure for processing a wafer Wwith the use of the above coating and developing apparatus, withreference to FIGS. 1 and 2. Herein, there is described an example inwhich a bottom anti-reflection film (BARC) is formed on a surface of awafer W, and a non-topcoat resist is coated on the bottomanti-reflection film as an upper layer. At first, the carrier 10accommodating, e.g., twenty-five wafer W is placed on the stage 11.Then, the opening and closing part 12 and a lid of the carrier 10 areopened, and a wafer W is taken out therefrom by the conveying means A1.Then, the wafer W is transferred to the main transfer means A2 via atransfer unit (not shown) as one of the levels of the shelf unit U1, anda bottom anti-reflection film (BARC) is formed on a surface of the waferW, which is a preprocess of a coating process, in the unit (BCT) 23, forexample. Thereafter, the wafer W is transferred by the main transfermeans A2 to the heating part as one of the shelves of the shelf units U1to U3, and the wafer W is pre-baked (CLHP) and then cooled. After that,the wafer W is loaded into the coating unit (COT) 24 by the maintransfer means A2, and a non-topcoat resist is coated on the overallsurface of the wafer W to form a thin film thereof. Subsequently, thewafer W is transferred by the main transfer means A2 to the heating partas one of the shelves of the shelf units U1 to U3, and the wafer W ispre-baked (CLHP) and then cooled. After that, the wafer W is transferredto the interface part 3 via the transfer unit of the shelf unit U3. Inthe interface part 3, the wafer W is transferred to the exposure part 4by the first wafer transfer part 30A of the first chamber 3A and thesecond transfer part 30B of the second transfer chamber 3B. In theexposure part 4, an exposure means (not shown) is arranged so as to beopposed to the surface of the wafer W, so that an immersion exposure isperformed. The wafer W, which has been subjected to the immersionexposure process, is transferred to the main transfer means A3 along areverse way, and is loaded into the developing unit (DEV) 25. The waferW, which has been loaded into the developing unit (DEV) 25, is subjectedto the above-described pre-wetting process by the developing apparatus50. Namely, there is performed the pre-wetting process in which,simultaneously with a developer 100 being discharged (supplied) from thedeveloper nozzle 52 that is located on a position near a central part ofa front surface of a wafer W that is being rotated by driving therotating mechanism 42, a deionized water 200 is discharged (supplied)from the deionized-water nozzle 53 that is located on a position nearerto an outer peripheral part of the wafer W than the developer nozzle 52,to thereby spread out the developer 100 in the rotating direction of thewafer W by a wall 300 that is formed by the deionized water 200 flowingthe outer peripheral side of the wafer W with the rotation of the waferW. After the pre-wetting process, the wafer W is subjected to a seriesof processes such as the developing process, the rinsing process, andthe drying process, whereby a predetermined resist pattern can beformed.

After that, the wafer W is unloaded from the developing unit (DEV) 25 bythe main transfer means A3, and is returned to the original carrier 10on the stage 11 via the main transfer means A2 and the conveying meansA1. In this manner, a series of coating and developing process iscompleted.

In the above embodiment, there has been described the example in whichthe bottom anti-reflection film (BARC) is formed on the surface of thewafer W, and the resist layer is formed on the surface thereof. However,when the bottom anti-reflection film (BARC) is omitted, the same effectas that of the above embodiment can be produced. In this case, the waferW is subjected to the resist coating step, the pre-baking step, theimmersion exposure step, the post-exposure baking step, and thedeveloping step (pre-wetting process, the developing process, therinsing process, and the drying process) in this order.

In the above embodiment, there has been described the example in whichthe developing apparatus according to the present invention is appliedto the developing process of the wafer W coated with the non-top resistcoat. However, this invention may be applied to a developing process ofa wafer W which is coated with a general resist other than thenon-topcoat resist. Moreover, this invention may be applied to adeveloping process of a wafer W having a highly water-repellent upperprotective film.

The invention claimed is:
 1. A developing method comprising a developingstep in which, while a horizontally held substrate having a resist filmformed thereon is being rotated, the substrate is developed by supplyinga developer onto a surface of the substrate, wherein provided before thedeveloping step is a pre-wetting step in which, simultaneously with thedeveloper being supplied from a first nozzle that is located on aposition near a central part of the surface of the rotating substratehaving a resist film formed thereon, a second liquid is supplied from asecond nozzle that is located on a position nearer to an outerperipheral part of the substrate than the first nozzle, to therebyspread out the developer in the rotating direction of the substrate by awall that is formed by the second liquid flowing to the outer peripheralside of the substrate with the rotation of the substrate, wherein, inthe pre-wetting step, the supply of the developer is initiatedsimultaneously with the supply of the second liquid, and wherein asurface tension value of the developer is larger than that of the secondliquid.
 2. The developing method according to claim 1, wherein thesecond liquid is a deionized water.
 3. The developing method accordingto claim 1, wherein a specific gravity of the developer is larger thanthat of the second liquid.
 4. The developing method according to claim1, wherein a viscosity of the developer is larger than that of thesecond liquid.
 5. The developing method according to claim 1, wherein arotational speed of the substrate is between 250 rpm and 3000 rpm. 6.The developing method according to claim 1, wherein before the developerand the second liquid are simultaneously supplied, there is provided astep in which the second nozzle is moved to a position above the centralpart of the substrate, and the second liquid is supplied onto thesubstrate surface.
 7. A developing method comprising a developing stepin which, while a horizontally held substrate having a resist filmformed thereon is being rotated, the substrate is developed by supplyinga developer onto a surface of the substrate, wherein provided before thedeveloping step is a pre-wetting step in which, simultaneously with thedeveloper being supplied from a first nozzle that is located on aposition near a central part of the surface of the rotating substratehaving a resist film formed thereon, a second liquid is supplied from asecond nozzle that is located on a position nearer to an outerperipheral part of the substrate than the first nozzle, and the firstnozzle and the second nozzle are moved in a direction connecting thecentral part and the outer peripheral part of the substrate, to therebyspread out the developer in the rotating direction of the substrate bymeans of a wall that is formed by the second liquid flowing to the outerperipheral side of the substrate with the rotation of the substrate,wherein, in the pre-wetting step, the supply of the developer isinitiated simultaneously with the supply of the second liquid.
 8. Thedeveloping method according to claim 7, wherein the second liquid is adeionized water.
 9. The developing method according to claim 7, whereina surface tension value of the developer is larger than that of thesecond liquid.
 10. The developing method according to claim 7, wherein aspecific gravity of the developer is larger than that of the secondliquid.
 11. The developing method according to claim 7, wherein aviscosity of the developer is larger than that of the second liquid. 12.The developing method according to claim 7, wherein a rotational speedof the substrate is between 250 rpm and 3000 rpm.
 13. The developingmethod according to claim 7, wherein before the developer and the secondliquid are simultaneously supplied, there is provided a step in whichthe second nozzle is moved to a position above the central part of thesubstrate, and the second liquid is supplied onto the substrate surface.